Tech I'm skeptical of and why

I’m a fan of people trying things, even if they seem silly. Dismissing risky ideas misses the point of research. But thoughtful criticism can direct effort to promising fields. To that end, I’m going to try to make my criticism as constructive as possible, with concrete reasons for my pessimism and closely related research areas which are promising (and stand to benefit even from failures in the field I’m criticizing). Not every section will live up to that standard; some arguments are built on vibes alone. I might be wrong, so I still want to see people work on these problems.